Abstract: A method, system, and computer program product for locating a network fault are provided in the illustrative embodiments. A set of network probes is configured to execute at a corresponding set of networking components in a data network. A set of events is received. An event in the set of events includes a list of network probes in an order those network probes are visited, the list of network probes forming a path in a set of paths. A test is performed to determine whether a fault condition is present in any of the paths. Those paths are selected, as a set of candidate paths, where the fault condition is present. At least one segment of a specified length is located that is common to a threshold number of paths in the set of candidate paths. The located segment is suggested as the location of the network fault.

Abstract: A switch unit, which is connected to one or more computers and one or more storage systems, comprises an update function for updating transfer management information (a routing table, for example). The storage system has a function for adding a virtual port to a physical port. The storage system migrates the virtual port addition destination from a first physical port to a second physical port and transmits a request of a predetermined type which includes identification information on the virtual port of the migration target to the switch unit. The transfer management information is updated by the update function of the switch unit so that the transfer destination which corresponds with the migration target virtual port is the switch port connected to the second physical port.

Abstract: A method is implemented by a network element for determining a next hop of a backup path for a fast reroute process to be utilized in response to a network event invalidating a primary path to a destination node. The method reduces computational requirements of the network element by reducing a number of paths to be evaluated without affecting selection of the backup path. The method selects a neighbor node P of a source node S to calculate a shortest path tree (SPT) for P for use in identifying backup paths for S. The SPT is calculated for P, pruning paths from the SPT that traverse S or that fail an LFA condition. P is selected for the next hop of the backup path for a destination node X where the SPT of P provides an LFA path from S to the destination node X.

Abstract: A network control system that achieves high availability for forwarding state computation within a controller cluster by replicating different levels of table state between controllers of the controller cluster. To build a highly available controller cluster, the tables for storing the forwarding state are replicated across the controllers. In order to take responsibility for a slice, the slave controller of some embodiments performs merging of replicated state on a slice-by-slice basis. The merging is performed in a manner to prevent disruptions to the network state while the slave controller is updated.

Abstract: A method of processing state information relating to user equipment in a communications system comprising a radio access network, the method comprising: maintaining current state information relating to the user equipment; and on the basis of a change of connection of the user equipment from a first cell to a second cell: transmitting a current value associated with a given state information part to the target radio access node in response to detecting at least one of one or more predetermined triggers that indicate that the target radio access node may not have received the current value from the source radio access node; or relying on the target radio access node having received the current value from the source radio access node if said at least one of said one or more predetermined triggers is not detected.

Abstract: The invention relates to a method in a user equipment and a user equipment (700) for controlling connection re-establishment between said user equipment and a network. The method comprises the steps of—receiving (501) a configuration message from the network defining at least one condition;—upon detection of connectivity problems (503) towards the first cell, evaluating said at least one condition (504);—if said at least one condition is fulfilled for a neighboring cell (B), applying at least one special criterion for initiating connection re-establishment to said neighboring cell (505), said at least one special criterion being different from at least one criterion that is applied if said at least one condition is not fulfilled. The invention furthermore relates to a method and an arrangement in a network node (800) for controlling connection re-establishment between the network and a user equipment (700).

Abstract: When stored identifying information of a transmission target frame and identifying information of a received frame are equal, a node apparatus updates transmission feasibility information stored in association with the final destination of the received frame. The transmission feasibility information indicates feasibility of transmission to each of a plurality of adjacent node apparatuses being a transmission destination, and is updated so that feasibility of transmission to the transmission destination associated with the identifying information of the received frame indicates that “the transmission is infeasible”. The node apparatus transmits the received frame, when there is no adjacent apparatus to which transmission is feasible, and when the stored identifying information of the transmission target frame is equal to the identifying information of the received frame, to the adjacent node apparatus recognized as the origin in association with the identifying information of the received frame.

Abstract: The method that is disclosed enables specific information network traffic flows to retain packet ordering in a packet network in which multipath techniques are used. In a common network usage a plurality of traffic flows may be aggregated into a larger traffic flow. In such a situation, a finest granularity of individual traffic flow is referred to as a microflow and an aggregation of traffic flows is referred to as a traffic aggregate. The traffic aggregate may take a path from an ordered set of nodes including a first network element referred to as an ingress node through zero or more intermediate network elements referred to as midpoint nodes, to a final network known as the egress node. The ordered set of nodes traversed by such a traffic aggregate is referred to as the path taken by that traffic flow. At any node prior to the egress, the traffic aggregate may be split among multiple links or lower layer paths in reaching the next node in the path.

Abstract: The present invention relates to a method and a network node for service instance management in telecommunications network. According to the method a plurality of network paths are monitored. A number of network paths form a protection group associated with a service instance or group of service instances. The monitoring of the network paths includes periodic transmission of CCMs on the network paths. To facilitate detection of mismatches related to protection switching, some CCMs include a mismatch information element that specifies traffic status of a working network path and of a protection network path for a set of protection groups. The set of protections groups includes the protection groups which the monitored network path is a member of. A CCM that includes the mismatch information element also includes an indication bit that indicates presence of the mismatch information element in the CCM.

Abstract: Transmission equipment includes: a first interface unit configured to receive a frame; and a second interface unit configured to transmit the received frame received by the first interface unit. The second interface unit includes a transmission circuit configured to transmit path information that represents a state of a logical path pair including a work path and a protection path provided for the received frame to the first interface unit. The first interface unit includes a destination determination circuit configured to determine a destination of the received frame based on the state of the logical path pair represented by the path information received from the second interface unit.

Abstract: A wireless communication network and a mobile device may support Circuit Switched (CS) and Packet Switched (PS) services. Some types of communication services (e.g. voice, text, data, etc.) may be supported using a CS service or using a PS service. In some embodiments, the PS service is an IMS service using Session Initiation Protocol (SIP) to provide a “CS-like” communication service such as voice or text message. According to the disclosure, a mobile device may detect that it is process data for the PS service. For example, a SIP component that supports the PS service may become inoperable. In response, the mobile device attempts to support the communication service using the CS service.

Abstract: Mechanisms are provided to improve efficiency of systems operating on internet protocol (IP) over Infiniband (IB) networks. One mechanism includes multicasting a first ARP request from a source node, the first ARP request including an IP address of a source port of the source node, and performing load-balancing of host traffic across a plurality of ports of a plurality of nodes by sending a reply from a destination node corresponding to the IP address included in the first ARP request, the reply being sent over the source port to the source node.

Abstract: A first terminal-side routing control device 13 is placed between a first communication network 21 and a first communication terminal 11. A second terminal-side routing control device 15 is placed between a second communication network 22 and a second communication terminal 12. The first terminal-side routing control device 13 includes a first via information setting unit 14 for including, in data received from the first communication terminal 11, information for specifying a routing control device 33 placed on one side of a long-distance transmission path 23 as a via device. The second terminal-side routing control device 15 includes a second via information setting unit 16 for including, in data received from the second communication terminal 12, via information for specifying a routing control device 34 placed on the other side of the long-distance transmission path 23 as a via device.

Abstract: For transmitting packets over radio communication links wherein flows of packets are delivered containing protected packets and unprotected packets, the status of propagation of the packets is verified in order to detect the presence of a faulty condition. If no faulty condition is detected, protected packet are transmitted over a first radio link wherein the transmission occupies a first portion of available bandwidth on the first radio link, and unprotected packets are transmitted on at least part of the remainder of the available bandwidth of the first radio link and at least part of available bandwidth the second radio link.

Abstract: A method and system for managing a backup service gateway (SGW) associated with a primary SGW, comprising periodically receiving from the primary SGW at least a portion of corresponding UE session state information, the received portion of session state information being sufficient to enable the secondary SGW to indicate to an inquiring management entity that all user sessions associated with a group of mobile devices supported by the primary SGW are in a live state; and in response to a failure of the primary SGW, assuming management of IP addresses and paths associated with the primary SGW and causing each UE supported by the failed primary SGW to reauthorize itself to the network.

Abstract: In a hierarchical switching architecture that includes at least one lower level managed switching element that connects to several higher level managed switching elements, some embodiments provide a method of identifying a higher level managed switching element to which the lower level managed switching element forwards a packet for further processing. The method computes a value based on a set of attributes of the packet. The method identifies a record from a hierarchy traversal table based on the computed value. The record specifies (1) a first higher level managed switching element as a primary higher level managed switching element and (2) a second higher level managed switching element as a secondary higher level managed switching element. The primary and secondary higher level managed switching elements are for forwarding the packet for further processing. The method forwards the packet to one of the higher level managed switching elements.

Abstract: In one example, a network device includes a hardware-based processor, and a Resource Reservation Protocol with Traffic Engineering extensions (RSVP-TE) module executing on the hardware-based processor that establishes a plurality of label switched paths (LSPs) having the network device as a common transit network device. The network device presents a plurality of options for selection, which each specify a different algorithm for selecting LSPs to evict from the link. In response to detecting an over-subscription condition on a link along the plurality of LSPs, the RSVP-TE module selects a subset of the plurality of LSPs to evict from the link, and the RSVP-TE module outputs an error message to one or more ingress network devices associated with the selected subset of LSPs without outputting an error message to the ingress network devices associated with those LSPs not selected for eviction.

Abstract: A system, method, and node for releasing resources in a telecommunications network. The method begins by a node assigning a resource-Identification (ID) to an internal resource within the node. At least one internal resource is allocated by the node for a specific Packet Data Network (PDN) connection. Next, a first message containing a resource-ID of the allocated internal resource is sent to one or more peer nodes. The peer nodes store the received resource-ID from the first message. When a node determines that a malfunction of the allocated internal resource of the node occurs, the node sends a second message containing the resource-ID of the malfunctioning internal resource to the peer nodes. The peer nodes then tear down the PDN connection.

Abstract: A network scanner, communication protocols, and client and server programs and are provided which provide an improved way to transmit legally binding documents, obviating the need for outmoded, legacy fax transmissions. Using the network scanner, a document may be scanned and transferred directly into any shared folder inbox residing on any computer attached to the Internet. Enhanced server systems and network communications and messaging protocols are provided that are more practical to use than email for sending documents such as executed legal documents or other documents requiring robust integrity and authenticatability. Similarly, the inventive network scanner, server systems and communication protocols provide improved ways to perform large file transfers and to manage bandwidth to minimize problems associated with uploading/downloading large files as attachments to/from email servers and for enabling user control over VoIP quality during file transmission sessions.

Abstract: A network switch including a plurality of stack units sequentially linked to each other. Each stack unit includes a port, a forwarding engine, a first interface, and a second interface. The second interface of each stack unit is linked to the first interface of a subsequent stack unit. The second interface of a last stack unit is linked to the first interface of a first stack unit. In response to a packet traveling in a first direction from the first stack unit to the last stack unit and a link between a second stack unit and a third stack unit being inoperative, the forwarding engine of the second stack unit returns the packet in a second direction to a preceding stack unit. The packet travels in the second direction from the preceding stack unit to the first stack unit, to the last stack unit, and to the third stack unit.

Abstract: A method for providing ingress fault protection in a label switched network, comprising sending data traffic from a source node to a first label switched path (LSP) via a first ingress node, detecting a first fault using a first fault detection link between the source node and the first ingress node, sending the data traffic from the source node to a second LSP via a second ingress node in response to detecting the first fault, detecting a second fault using a second fault detection link between the first ingress node and the second ingress node, and merging the data traffic from the second LSP into the first LSP at a next-hop node of the first ingress node, wherein the data traffic is no longer sent to the first LSP via the first ingress node after the first fault.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for semi-centralized routing. In one aspect, a computer-implemented method receives a network protocol packet at a router adapted for routing data packets to one or more additional routers. The network protocol packet conforms to a routing protocol that provides distributed routing computation. The method also sends the network protocol packet, through a controller, to a selected one of a plurality of route control servers. The method also processes the network control packet at the selected route control server to generate a routing computation result that conforms to the routing protocol. The method also generates routing information based on the routing computation. The routing information conforms to a control protocol that provides centralized routing computation. The method also sends the routing information to the router for routing of data packets based on the control protocol.

Abstract: A method for binding physical network ports for network communications creates in an application layer virtual ports that correspond to virtual network cards. Each virtual port is capable of being bound in the application layer with other created virtual ports. Multiple physical network ports, which need to be bound, are added to the created virtual ports. To receive or transmit a packet, one or more available physical network ports are selected according to a configured mode for receiving or transmitting the packet. If the configured mode is a server load balancing mode, a physical network port that corresponds to a quintuple of the packet is identified, and the packet is received or transmitted through the identified physical network port. When no corresponding physical port is found, a physical network port with minimum traffic is selected for receiving or transmitting the packet.

Abstract: A method performed by a provider edge device includes generating pseudo-wire tables based on virtual private local area network service advertisements from other provider edge devices, where the provider edge device services customer edge devices, and establishing pseudo-wires with respect to the other provider edge devices, based on the pseudo-wire tables, where the pseudo-wires include an active pseudo-wire and at least one standby pseudo-wire with respect to each of the other provider edge devices. The method also includes generating and advertising VPLS advertisement to the other provider edge devices, detecting a communication link failure associated with one of the customer edge devices in which the provider edge device services, and determining whether the at least one standby pseudo-wire needs to be utilized because of the communication link failure.

Abstract: A data transmitting device coupling to a plurality of nodes in a network includes a plurality of communication paths, the data transmitting device includes a memory and a processor coupled to the memory configured to set a routing table based on a command that designates a first communication path included in the plurality of communication paths, to detect a link failure occurred in the network, and when the link failure has occurred at a first location between the data transmitting device and a first node adjacent to the data transmitting device on the first communication path, to modify the routing table so that data are to be transmitted to a second node on a second communication path different from the first communication path, and when the link failure has occurred at a second location that differs from the first location in the network, to maintain the routing table.

Abstract: Apparatus, method and program for restoring path information to its original status when a trouble occurs on a network. An apparatus control part generates, based on a switch information list and an I/F information list stored in a nonvolatile storing part, link information that is prior to the reactivation and used for determining adjacent communication apparatuses. The apparatus control part acquires, via a control network from the adjacent communication apparatuses described in the generated link information, held path information. Thereafter, the apparatus control part (11) decides, based on a stored definition information list, a path sequence such that the path of a lower order layer is placed before the path of an upper order layer. Thereafter, the apparatus control part generates the path information based on the path sequence and further based on the previously acquired held path information.

Abstract: In one embodiment, a working path through a packet switched network is protected by a protection path. In response to a switchover condition, a packet switching device ceases to enqueue packets for sending over the current working path. Packets are enqueue for sending over the protection path, with a delay by a predetermined duration before beginning to dequeue and send of packets over the protection path. A sending packet switching device, by delaying an appropriate predetermined duration, can guarantee that the protection switching operation will not induce packet reordering nor packet loss. This predetermined delay is calculated, possibly based on measurements, of different component delays of sending packets over the working and protection paths. For example, these component delays typically include latency within the sending device, latency of communications between the sending device and the destination, and latency with the destination.

Abstract: A method for application broadcast forwarding for routers running redundancy protocols in a network is provided. The network includes a first router running at least one program instance of a redundancy protocol at one interface, and a second router running at least one program instance of the redundancy protocol at one interface. A relay agent is enabled on both the first and second routers. The method includes, for each router, determining at least one preference ID for the router, determining a broadcast ID of each incoming broadcast packet, matching the broadcast ID of the incoming broadcast packet with the at least one preference ID of the router, and relaying the incoming broadcast packet from a first network domain to a second network domain if the broadcast ID of the incoming broadcast packet matches one preference ID of the router.

Abstract: In one embodiment, a packet switching device sends packets to be sent from a single link of a bundled link interface to multiple egress network processing units (on a same or different line cards). A single one of these multiple egress network processing units is configured to be in the active mode sending particular sets of packets. The other egress network processing units are configured for these particular sets of packets to be in the non-active mode, and hence, will correspondingly drop these particular sets of packets. In case of failure, an egress network processing unit can quickly (e.g., changing a flag) be changed to the active mode to quickly reduce or eliminate loss of packets.

Abstract: A method and apparatus that promote expedited fast link failover decisions by and end station with redundant multilayer switching paths to a network are disclosed. In response to detecting a change in connectivity with an upstream link to a network, an upstream switch may send a notification to an intermediate switch with a downstream link to the end station. In response to the notification, the intermediate switch may disable (“bring down”) the downstream link to the end station. Bringing the downstream link down in this manner may cause the end station to switch (“failover”) to a different downstream link, for example, allowing the end station to establish connectivity to the network via a redundant path.

Abstract: The present disclosure relates to a network protection scheme. In one embodiment, there provides a method for network protection, including the steps of: detecting a switch indicator in a network; setting a rate limit of storm protection, which is of a first value, as a second value, the second value being higher than the first value; and performing a flush operation of a Forwarding DataBase FDB.

Abstract: A method of operating a control plane having a centralised network management system (10), control domain servers (20) and a plurality of forwarding elements (30), for controlling respective network entities (L2), and grouped into control domains (21, 22, 23). Each domain has a control domain server. Automatic checking for inconsistencies (110, 115, 210, 310, 320, 450) between the records held at the different parts of the control plane, involves comparing checklists of the records of the circuits stored at the different parts of the control plane. If an inconsistency is found, there is automatic updating (120, 220, 230, 460) of the records using a copy sent from another of the parts of the control plane. The checklists can avoid the need to forwarding entire copies.

Abstract: A secondary edge node is coupled between the packet network and a non-packet network and is adapted to function as follows when a failure associated with the primary edge node or circuitry coupled thereto occurs. First, the secondary edge node may detect a failure associated with the primary edge node, which is associated with a primary media access control (MAC) address that is used to direct the packet traffic from the first edge node to the primary edge node. Upon detecting the failure, the secondary edge node may send a switch request message including a secondary media access control address that is associated with the secondary edge node to the first edge node. Sending the switch request message indicates that the first edge node should start sending traffic for the first session to the secondary edge node using the secondary media access control address.

Abstract: When stored identifying information of a transmission target frame and identifying information of a received frame are equal, a node apparatus updates transmission feasibility information stored in association with the final destination of the received frame. The transmission feasibility information indicates feasibility of transmission to each of a plurality of adjacent node apparatuses being a transmission destination, and is updated so that feasibility of transmission to the transmission destination associated with the identifying information of the received frame indicates that “the transmission is infeasible”. The node apparatus transmits the received frame, when there is no adjacent apparatus to which transmission is feasible, and when the stored identifying information of the transmission target frame is equal to the identifying information of the received frame, to the adjacent node apparatus recognized as the origin in association with the identifying information of the received frame.

Abstract: The present invention provides an Ethernet ring system, transit node of Ethernet ring system, and initialization method thereof, wherein the method includes the following steps: step 1, generating a transit node of Ethernet ring protection domain by means of ring nodes; step 2, detecting the link state of two ring ports by means of the transit node: if neither of the two ring ports is detected as in-fault, then recording ring the link state as initialization state, blocking at least one of the ring ports, setting the at least one blocked port in prerelease state, and sending a ring state query packet to a master node, by means of the transit node; step 3, when the ring state query packet is received, sending a ring state packet recorded by the master node to the ring port that receives the ring state query packet, by means of the master node; and step 4, checking whether the ring state packet sent by the master node have been received by the transit node of which the ring state is the initialization state; if

Abstract: When a first line card receives a frame at a port, the line card refers to monitoring results by internal communicability monitoring units of other second to fourth line cards and a monitoring result by an internal communicability monitoring unit of its own, determines a first band limiting unit of a transmission destination from band limiting units of other line cards based on the monitoring results, and transmits the frame. The second line card limits the communication band of the frame by the first band limiting unit of its own, and transmits the frame to a predetermined port. If any fault is detected in the communicability in the internal communicability monitoring table to/from the second line card as the communication counterpart, and, if the communicability to/from the third line card as the communication counterpart is normal, the first line card changes the transmission destination into the second band limiting unit.

Abstract: Hypervisor functions, which may control operations of one or more virtual machines, may be distributed across a plurality of network devices. State information may be stored for the virtual machines on network devices for fault tolerance and resilience. The virtual machines may retrieve stored state information to recover from a fault. The hypervisor may control the storage of the state information. Resources of the network devices may be allocated for fault tolerance and resilience of the virtual machines based on network device parameters, which may include storage capacity, processor usage, access time, communication bandwidth, and/or latency. The state information may include program content, cache content, memory content, and/or register content information, may be stored on a continuous, periodic, or an aperiodic basis, and may be shared among the network devices to enable the processing of data by the virtual machines when a fault occurs, and may be incrementally updated.

Abstract: A method is provided of obtaining information representative of an availability of a communications network, which includes a plurality of equipment exchanging routing data in accordance with a routing protocol. The method includes a stage of storing in chronological order at least some of the routing data exchanged between at least one first equipment and at least one second equipment; a stage of totaling unavailability times as a function of the routing data stored in chronological order for a predetermined time period; a stage of obtaining the information representative of an availability for the time period as a function of the totaled unavailability times.

Abstract: A system may include a device that receives requests to initiate a videoconference call. The requests may include an indication of a service priority tier that should be applied to the call and first and second client devices for the call. The system may determining bandwidth availability in a network and determine, based on the bandwidth availability and based on the indication of the service priority tier of the call, whether to admit the videoconference call to the network. The device may provision, when it is determined to admit the call to the network, traffic policies corresponding to one or more network devices, where the policies are determined based on the service priority tier of the videoconference call.

Abstract: A wireless communication system (20) includes an ability to discern whether an end of a communication link between a mobile station (22) and a base station (26) corresponds to the mobile station (22) tuning away from a first service to a second, different service. In a disclosed example, a radio network controller (28) includes a link monitoring portion that uses information regarding the mobile station from the second service to determine a pattern of expected tune aways by the mobile station to the second service. In one disclosed example, the link monitoring portion uses observed mobile station behavior to estimate the pattern of expected tune aways. Whenever an end of a communication link with the mobile station corresponds to an expected tune away, that end is not considered for purposes of service measurement parameters.

Abstract: In an embodiment, a method is provided. The method of this embodiment provides in response to receiving a packet, looking up a packet characteristic in one of at least one protocol table to determine one or more fields of the packet to use as a hash value, applying a hash function to the hash value to obtain a hash result, and using the hash result to determine one of a plurality of processors on which to process the packet.

Abstract: A method and an apparatus for rapidly resuming, at times of failures, network traffic in a connection-oriented network by using an alternative route pre-computed and stored locally in nodes along an initial route without requiring signaling of upstream nodes or a master server.

Abstract: A method in a router for initiating fast flooding based fast convergence to recover from a network failure is disclosed. The method also starts with detecting a network failure. Responsive to the detected network failure, the router floods a layer 2 fast failure notification message out a set of one or more interfaces of the router. The fast failure notification message includes information that identifies the network failure and indicates to a router that receives the fast failure notification message to flood the fast failure notification message out its interfaces that are not blocked by a spanning tree protocol (STP) independently of updating its routing table to reflect the network failure. The method continues with the router updating a routing table to reflect the network failure.

Abstract: In some example embodiments, there is a method for failback to a primary communications adapter. The method includes receiving, in a driver for the primary communications adapter and a backup communications adapter, a link up event for the primary communications adapter, wherein the link up event is sent from the primary communications adapter to the driver, and wherein the link up event is triggered by establishing electrical connectivity to the primary communications adapter. The method includes inferring that the primary communications adapter is configured for receiving packets. The method includes setting the backup communications adapter to idle, wherein the backup communications adapter receives packets and drops the packets while idle. The method includes activating the primary communications adapter, wherein the primary communications adapter receives packets and passes the packets up a protocol stack while activated.

Abstract: System for early detection of decoding errors. A method is provided for detecting a decode failure. The method includes receiving an initial amount of code packets, detecting a trigger event that indicates a decode failure associated with the initial amount of code packets, and receiving one or more additional code packets.

Abstract: A system and method for fault isolation in a packet switching network, wherein a network element may be categorized as faulty when the network element is identified as a point-of-congestion in the network. One such system can be broadly summarized by a representative communication system that incorporates a fault isolating element to monitor multiple network elements. The fault isolating element includes components such as a database of data flow paths that exist in the plurality of network elements, a data gathering element that is configured to collect performance information related to one or more network elements, and an analyzer element that uses the performance information collected by the data gathering element to identify one or more network elements as points of congestion.

Abstract: A node 800 of a multi-layer communication is capable of routing a message signal via one or more different layers (for example a PSC layer, TDM layer, LSC layer) in the multi-layer communication network. The node 800 comprises a first interface 801 for receiving a path message 803 containing routing information for routing an associated message signal through the multi-layer communication network. One or more second interfaces 805i to 805N are provided for transmitting a message signal to one or more respective layers in the multi-layer communication network. A processing unit 807 is adapted to determine if the path message 803 contains protection information 40 indicating that protection switching is to be performed in one or more different layers of the multi-layer communication network, and if so, establish a protection switching mechanism in the one or more different layers using the protection information 40 provided in the path message 803.

Abstract: A method, device, and system for dual-uplink tangent ring convergence, where ports on a network device are classified into conjugate ports and non-conjugate ports. When receiving an entry update packet from a first port or perceiving a state change of a first port, when it is determined that the first port of the network device is a conjugate port, the network device clears a media access control (MAC) entry and an Address Resolution Protocol (ARP) entry that use the first port as an outbound interface and clears all MAC entries that use a non-conjugate port as an outbound interface, in a MAC table and an ARP table of the network device. In this way, traffic interruption can be avoided, wherein a failure of one dual-uplink tangent ring does not cause an entry of one or more other normal dual-uplink tangent rings to be cleared/updated.

Abstract: A method, apparatus and computer readable medium for maintaining two variables per port member of a network device which is part of a Split Multi Link Trunk/Link Aggregation Group (SMLT/LAG) is presented. A first variable comprising a link status variable reflecting a link status, and a second variable comprising a forwarding status variable reflecting a forwarding status of a forwarding plane with respect to the port are provided, the link status variable and the forwarding status variable in a first state when the port is operating properly. A failure related to the port is detected. The link status variable is set to a second state, and the forwarding status variable is set to a second state.

Abstract: A system for interfacing a client system in a first network domain with a Provider Link State Bridging (PLSB) domain includes at least two Backbone Edge Bridges (BEBs) of the PLSB domain. Each BEB is an end-point of a connection in the first network domain to the client system and an end-point of at least a unicast path in the PLSB domain. An inter-node trunk is provided in the PLSB domain for interconnecting the BEBs. A phantom node is defined in the PLSB domain and is notionally located on the inter-node trunk. Each of the BEBs is configured such that: an ingress packet received from the client system via the connection in the first network domain is forwarded through a path notionally rooted at the phantom node; and an egress packet destined for the client system is forwarded to the client system through the connection in the first network domain.